Derivative of \( \displaystyle - \sqrt{x^{2} - 2 x + 2} \)
Problem 2.1831 · hard
Differentiate \( \displaystyle f(x) = - \sqrt{x^{2} - 2 x + 2} \).
- \[ \frac{d}{d x} \left(- \sqrt{x^{2} - 2 x + 2}\right) \]derivativeStart with the derivative of the function.✓ Proved
- \[ = - \frac{d}{d x} \sqrt{x^{2} - 2 x + 2} \]constant-multiple rewritePull out the constant -1. Rewrite the square root using the exponential and logarithm.✓ Proved
- \[ = - \sqrt{x^{2} - 2 x + 2} \frac{d}{d x} \frac{\ln{\left(x^{2} - 2 x + 2 \right)}}{2} \]chainApply the chain rule for the exponential function.✓ Proved
- \[ = - \frac{\sqrt{x^{2} - 2 x + 2} \frac{d}{d x} \ln{\left(x^{2} - 2 x + 2 \right)}}{2} \]constant-multiplePull out the constant 1/2.✓ Proved
- \[ = - \frac{\frac{d}{d x} \left(x^{2} - 2 x + 2\right)}{2 \sqrt{x^{2} - 2 x + 2}} \]chainApply the chain rule for the logarithm.✓ Proved
- \[ = - \frac{2 x - 2}{2 \sqrt{x^{2} - 2 x + 2}} \]derivative algebraDifferentiate the inner polynomial. Substitute the exponential expression back to its square root form.✓ Proved
- \[ = \frac{2 - 2 x}{2 \sqrt{x^{2} - 2 x + 2}} \]algebraCombine the terms into a single fraction.✓ Proved
- \[ = \frac{1 - x}{\sqrt{x^{2} - 2 x + 2}} \]simplifySimplify the fraction by canceling the common factor of 2.✓ Proved
Answer \( \frac{1 - x}{\sqrt{x^{2} - 2 x + 2}} \)
✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation.
The full receipt
| Line | Status | Checked by | Detail |
|---|---|---|---|
| 1 | ✓ Proved | sympy 1.14.0 | line 1 is the problem as stated |
| 2 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 3 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 4 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 log is undefined for non-positive arguments |
| 5 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 log is undefined for non-positive arguments |
| 6 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 log is undefined for non-positive arguments undefined where x**2 - 2*x + 2 = 0 |
| 7 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where x**2 - 2*x + 2 = 0 |
| 8 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where x**2 - 2*x + 2 = 0 |
| 9 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where x**2 - 2*x + 2 = 0 |
| 10 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where x**2 - 2*x + 2 = 0 |
| answer | ✓ Proved | sympy 1.14.0 | final line against the stated answer: simplify(a - b) reduced to 0 undefined where x**2 - 2*x + 2 = 0 |
| answer, a second way | ✓ Proved | sympy 1.14.0 | SymPy differentiated f directly and got the stated answer |
Reviewers
gpt-oss:20b: passqwen3.6:27b-mlx: pass — The solution correctly applies the chain rule and algebraic simplifications. Each step changes only one aspect of the expression and uses valid labels from the fixed vocabulary.
Every verdict on record (4)
qwen3.6:27b-mlx: pass 2026-10-08 — The solution correctly applies the chain rule and algebraic simplifications. Each step changes only one aspect of the expression and uses valid labels from the fixed vocabulary.gpt-oss:20b: pass 2026-10-08gpt-oss:20b: pass 2026-10-08qwen3.6:27b-mlx: pass 2026-10-08
Proved: SymPy reduced the difference between the two sides to zero. Checked independently: a separate
method, named above, confirmed it. Checked numerically: the two sides agree at every sampled point, which is evidence,
not proof. Reviewed: a model or a person read it; that is all a sentence can have. Solution by
gemma4:26b, checked 2026-10-08 with SymPy 1.14.0.